Track installation to control railway trains



Nov. 4, 1930. -r CLARK, ET AL TRACK INSTALLATION TO CONTROL RAILWAYTRAINS Original Filed May 20, 1927 6 Sheets-Sheet 1 Nov. 4, 1930. T. E.CLARK ET AL 1,780,416

TRACK INSTALLATION TU'CONTROL RAILWAY TRAINS Original Filed May 30, 19276 Sheets-Sheet 2 INVENTORS ATTORNE Nov. 4, 1930, T; E, CLARK ET AL1,780,416

TRACK INSTALLATION TO CONTROL RAILWAY- TRAINS Original Filed May 20,1927 6 SheetsSheet 3 ATTORNEY NOV. 4, 1930. I E, CLARK ET AL 1,780,416

TRACK INSTALLATION TOCONTROL RAILWAY TRAINS Original Filed May 20, 19276 Sheets-Sheet 4 m INVENTOR iififlgi ATTORNEY Nov'. 4, 1930. T. E. CLARKET TRACK INSTALLATION TO CONTROL RAILWAY IRAINS Original Filed May 20;1927 ATTORNEY Nov. 4, 1930. T. E. CLARK E 1,780,416

TRACK INSTALLATION TO CONTROL RAILWAY TRAINS Original Filed May 2 0,1927 6 Sheets-Sheet 6 mwa mwfiw ATTORNEY Patented Nov. 4, 1930 UNITEDSTATES PATENT OFFICE THOMAS E. CLARK AND JAMES E. CLARK, OF DETROIT,MICHIGAN, ASSIGNORS T CON- TINUOUS TRAIN CONTROL CORPORATION, OFDETROIT, MICHIGAN, A CORPORATION 01 MICHIGAN TRACK INSTALLATION T0CONTROL RAILWAY TRAINS Substitute for abandoned application Serial No.192,839, filed May 20, 1927. This application filed December 12,1929.

This invention relates to control systems for railway trains travelingtracks divided into blocks whereby one or both of two radio-frequencycurrents may be impressed upon the track rails at spaced stations inorder that electro-magnetic force or flux may be picked up from adjacentthe rails by receptors on the locomotives or other vehicles providedwith automatic brake installations and controlling instrumentalities forsuch brakes,so that the operation of the vehicle may be governed by suchradio-frequency currents, and its object is to provide transmissioninstrumentalities which will impress current of predetermined.

frequency upon the rails of a block when the block in advance isoccupied, and which will impress a current of another and preferablyhigher frequency upon the rails of a block when the block in advance isunoccupied, and which will impress both of said currents upon the railsof the last block of controlled track so that said instrumentalities onthe locomotive will respond thereto and render the automatic brakemechanism inoperative while the vehicle passes over the rails ofnoncontrolled territory, such trackway installations being soconstructed that no current is ii'npressed upon the rails of any blockunless such block is occupied.

A further object of this invention is to divide each block of controlledtrack of sufficient length into cut-sections and to impress such currenton only such sections as are occupied and to so adjust the transmissioninl strumentalities that substantially the same predeterminedelectro-inagnetic flux will be present in each cut-section in turn, asre quired.

Another obiect of this invention is to make use of well known andlargely-used railway signal systems to assist in the control of thetrain control instrumentalities.

The present application is a substitute for abandoned application,Serial No. 192,839, filed May 20, 1927.

In the accompanying drawings Fig. i is a diagrammatic view of a trackinstallation and three auxiliary current trans inittinginstrumentalities connected thereto,

Serial No. 413,689.

the mainniechanism being operatively'positioned for clear trackconditions.

Fig. 2is a view similar to Fig. 1 with fewer axillary instrumentalities,the parts being positioned fordangefitrack conditions, but non-operatinFig. 3 is a view of the instrumentalities shown in Fig. 2, butoperating.

Fig. 4 is a similar view of a track-side station not equipped withauxiliary instrumentalities.

Fig. 5 is a view similar to Fig. 3, but operating under a dilferenttrack condition.

. Fig. 6 is a diagrammatic View of a station adapted to transmit tworadio-frequency currents of different wave lengths simultaneously.

Figs. 7 and 8 are views illustrating the connections betweenthesemaphore and the control installations.

The rails in Figs. -1, 2, 3, and 5 of the the drawings are shown dividedinto cut-sections of blocks by insulations 1, preferably at points aboutone-half mile or 800 meters apart, although these distances may bevaried greatly, and at the ends of these blocks: the signal posts '10are shown conventionally. A. control station is located at the exit endof each block andthe direction of traffic is supposed to be from left toright. WVhen a block is occupied, no effective current passesfrom thecontrol ins runientalities at the exit end thereof along the railstoward the entrance end beyond the vehicle occupying the block, andanother vehicle entering in such block at its entrance end will not beaffected by current in the rails of two cut-sections 23 and 45 separatedby insulators 1. The trackway installations are energized by currenttaken from the wires 8 and 9 which carry A. 0. current of preferably 110volts. The several installations and the blocks controlled thereby aredesignated by the capital letters A and O to F inclusive, and the blockscontrolled by stations A, D and F are shown occupied by vehicle T, whileadjoining ends of the blocks controlled by stations E and F are shownoccupied by train TT. The signal post 10 at the end of each block isconnected to a switch 11 which controls one of the circuits connected tothe adjacent signal battery 18. Switch 11 is so constructed that itwill-be opened by the semaphore signal at danger, that is, when theblock is occupied at whose entrance end it is located, but this switchwill be closed when that block is unoccupied. While the occupancy of thenext block in advance is indicated by the signal, it has no effect onthe switch, which remains closed when the signal indicates caution orclear. Neither the signal nor the switch and the circuit controlledthereby need be considered as they form no part of the presentinvention, being merely shown to indicate that the present system willnot interfere with these parts of a signal system.

The relays 14, 15, 16 and 17 of the signal system are made use of,together with the battery 18. The several armatures of the relays areindicated by the small letters a and b and in the specification will bedesignated thereby together with the numeral pertaining to the relay.WVhile we speak of a plurality of armatures for relay 14 and others,these are in fact merely independent contacts on the same armature, butthe separate lettering is more convenient.

The relay 14 connects to the rails at the exit end of the controlledblock by means of wires 18 and 19 and is normally energized by the trackbattery 20 connected to the entrance end of the last cut-section of thatblock. Relay 17 at any station connects to the entrance end of the nextblock in advance by wires 21 and 22 and is normally energized by trackbattery 85 connected to the exit end of the first cut-section of thatblock.

The mechanism for impressing radio-frequency current upon the rails soas to create electromagnetic flux along the rails receives :5 itsoperative current from the line wires 8 and 9, the wire 27 adj ustablyconnecting the wire 9 to the primary winding 36 of the main transformer28, and the wire 29, armature 30 and wire 31 connecting this primarywinding to the line wire 8 when relay 30 is energized and wire 47, andback over wires 48. Thecurrent for the filament of tube 41 travels thewinding 42, wire 49 and back overwire 50.

The plate current of tube 41 travels from the filament of this tube tothe plate and thence over wire 52 to the top of winding 43, while theplate current of tube travels from the filament of that tube to theplate and thence over wire 53 to the winding 43. Choke coils 54 areinserted in these wires 52 and 53 to block the radio-frequencyoscillations and force them through the condensers 55 and 56 to beexplained later on.

The oscillatory, circuit which generates the traincontrol currents isgoverned by an inductance 57 and condensers 58 and 59, from betweenwhich the wire 60 extends to wire 67 and this wire 67 extends to theconnector 45. A grid leak 61 connects to wires 67 and 63, wire 63terminating in the grid of the tube 41 and connecting to one end of theinductance 57 and to the condenser 58. The other end of the inductance57 and the condenser 59 connect to the wire 64 which extends between thecondenser 55 and a grid condenser 65 and thence to the grid of tube 40.It will thus be seen that the grid and plate of tube 41 are connected tothe ends of the inductance 57 and condensers 58 and 59 whereby the tube41 is caused to produce oscillations of a predetermined frequency, thisbeing governed by the inductance 57 and the capacity of the condensers58 and 59.

The plate output of tube 41 being impressed upon the grid of tube 40,the oscillations of tube 40 are governed thereby, and therefore theplate output of this tube 40 is always of the same frequency as that ofthe tube 41, and this is unaffected by any connections or conductorswhich may be attached to the circuit of tube 40. The plate output oftube 40 passes through condenser 56 to primary 68 of the outputtransformer 69 and thence over the wire 67 terminating in connector 45.The grid of tube 40 is unloaded through a leak 70 connecting to thewires 64 and 67 and to connector 45. Practical tests have demonstratedthe advisability of using a tube 40 of fifty watts rating and a tube 41of seven and one half watts rating.

The output transformer 69 has a secondary winding 7 2 to the ends ofwhich the wires 73 and 74 connect, while a wire 75 connects to theadjustable contact 76, adjustable condensers 7 7 being connected intothe wires 73 and 75. We prefer to use the full length of the winding 72when transmitting current to the entrance cut-sections but use thecontact 76 to ing to one end of inductance 57, the armature a of relayand wire 81 connecting to a point intermediate the ends of thisinductance, is employed, the closing of this circuit shortening theinductance and increasing the rate of the oscillations and shorteningthe wave length of the current output. The circuits for this relay 80will be explained later on.

Two wires 83 and 84 extend between adjacent stations whenever the blocl;of the station in advance contains no more than two cut-sections, as isthe case with blocks B and E inclusive. Connected to the entrance end ofthe firstcut-section is the relay 17 as previously pointed out, while atrack battery 85 connects to the exit'end of such cut-section. Wires 86and 87 extend from the wires 88 and 84 to carry radio-frequency currentto the primary winding 88 of transformer 89, the secondary winding 90being connected to the rails 4 and 5 by wires 91 and 92 which also carrycurrent from battery 85, a choke coil 98 and condenser 94 being providedto protect the battery and transformer.

Now taking Figs. 2, 8 and 4, and assuming that block E is occupied bytrain TT (Fig. to cause signal D to indicate danger, the followingconditions occur in stations B, and. D. Vehicle T on rails 4 and 5 ofblock D short circuits relay C and opens the circuit from battery D torelay 0. This relay C controls the circuit to relay C and it it were notfor engineering reasons connected with'the signal system already in use,the feed wires of relay 15 of any station might be extended to relay 80of that station. The normal circuit under clear conditions for relay Cwhen relay D is energized as hereinafter explained, is from battery Dover wires 96 and 97, armature 16 wires 98, 84, and C. relay C wire 100,armature 17. wire 101, wires 83 and D armature 14, wire 103, relay 104,wire 105, armature 16, and wire 106 to battery D \Vires 83 and 84 extendonlybetween adjacent stations. The circuit for C has been traced underthe assumption that C" as well as D is energized. The normal circuit ofrelay D is open, but when closed by armature 15 is from battery D overwire 96, 107 and 108, relay 80, wire 109, armature 15, wire 110, droppedarmature 104 and wire 106 to the battery. This circuit would be closedit blocks E and F were-unoccupied, block D being occupied as shown. inthe drawing.

The relay 104 of each block is inseries with relay 15 of the nextstation in the rear and the circuit for both is controlled by the trackrelay 17 of such rear station. As the circuit of each relay 1'? isopened whenever the rails of the section to which it is connected, areoccupied or broken, or when any of the circuit wires of this relay 17are broken, it is evident that relays 104 and 15 at two consecutivestations will be tie -energized whenever relay 17 between them on thepresent drawing) is de-energized. So long as any relay 104 is energized,relays 30, 80, 114 and 115 of the same station are deenergized and suchstation is non-operating as will presently appear.

When relay 15 of any station is de-energized, relay 80 or that stationis also deenergized and should the block to which such station isattached be occupied, caution current will be transmitted to the railsof that block as will be explained later on.

The energizing circuit of relay 104 of block C is from battery C overwires 96 and 97 dropped armature 16, wire 105, relay 104, wire 103,raised armature 14*, wires 102, 83, B armature B wire 100, relay B wires99, 84, C dropped armature C and back to the battery. So long as thiscontinues, station C is non-operative, since relay 30 remainstie-energized. Should relay B be short-circuited because the entrancesection of block C is occupied, or relay C be shortcircuited because thesecond section of block 0 is occupied, then this circuit to relay C isopened. \Vhen neither of these sections is occupied and with block Dunoccupied, re-

lays C, C and B will be energized, relay C because switch 11 is closed,as will be explained later on in connection with Figs. 7 and 8. In thiscase the current will flow from battery C over wires 96 and 97, armature16", wires 98, 84, B relay B wire 100, armature 17", wires 101, 83, andC a1- mature C wire 103, relay C wire 105, raised armature 16 and wire106 back to the battery.

Relay 1) is receiving current because the first cut-section of block Dis occupied and relay 17 and relay 104 of station D are de-energizedbecause block E is also occupied. The circuit for this relay D is frombattery D over wires 96 and 107 to this relay and over wire 112, droppedarmature 104 and wire 106 to; the battery. lVhen relay 30 and theelectron tubes are energized, the flow ofra- Clio-frequency to the railsdepends upon the two relays 114 and 115. As the first cut-section ofblock D is occupied, relay C is deenergized and for that reason relay Dis de-energized as above described. Relay D receives battery currentfrom the battery D over wires 96, 107 and 116 and back over wire 117,armature 14, wires 118 and 112, dropped armature. 104 and wire 106 tothe battery. As armature D114% is attracted, the circuit ofradio-frequency current is from winding D over wire 74, armature 114wire 120, wires 98, 84 and 87, primary winding 88 of transformer 89attached to the rails of block I), armature 14 and Wires 103 and 73 tothe other end of winding 7 2.

Relay 80 is de-energized in Fig. 3, and current of longer wave length orcaution current is impressed upon the rails of block D. The full lengthof winding 72 is used to impress radio-frequency current on the primarywinding 88 of transformer 89, and this current is stepped down bytransformer 89.

In Fig. 5, station F is in clear condition, two blocks of the trackahead being unoccupied, as is indicated by signal F Rails 2 and 3 at theexit end of block F are occupied so that relay F becomes (lo-energizedthrough its battery 20 being short-circuited by vehicle T. Relay F opensthe battery circuit to relay F and closes the battery circuit to relay115 which is from battery F over wire 96, relay 115, wire 119, droppedarmature 14", wires 118 and 112, dropped armature 104 and wire 106 tothe battery. The circuit for radio-frequency current closed by armature115 is over wire 74, armature 115, wires 121 and 18 to rail 3, vehicle'1, rail 2, wires 19 and 75 to contact 76.

Relay 80 is shown energized in Fig. 5, shortening inductance 57 to causethe genera tion of radio-frequency current of higher or clear frequency,and the circuit for this relay 80 is over wires 96, 107 and 108, relay80, wire 109, armature 15, wire 110, armature 104 and wire 106 to thebattery. Energized relay 80 attracts its armature a which is connectedto inductance 57 between its ends and thereby shunts a portion of thisinductance. The shortening of the transformer winding 72 by means of thecontact 76 is not sufficient to vary the wave length, but is merely totune the winding to the circuits.

As the vehicle or train connects the rails, there will not be suilicientradio-frequency current between the rear end of this vehicle or trainand the entrance end of the block occupied by such rear end to affecttheinstrumentalities of a following train entering such block, and suchinstrumentalities will therefore assume danger positions. This is thecase with train TT which is entering occupied block F.

Block E is shown to be short and is not divided into cut-sections, sothat the mechanism comprising battery 20 and its relay are thereforeomit-ted, together with transformer 89 and its connections and relay 114and its connections. As the entrance cut-section of block F is occupied,relays 15 and 17 of station E are de-energized. As block F is alreadyoccupied, no radio-frequency current would be present in the rails atthe entrance end of block F. As the train TT extends back of theconnection of the wires 91 and 92 from track battery 85, relay D isde-energized and relay E is therefore ale-energized. The armatures ofrelays 30 and 80 of this station E assume caution positions, relay 30receiving battery current over wires 96 and 107, the return being overwire 121, 112, armature 104 and wire 106. Armature 30 being attracted,the tubes 40 and 41 and the transformer 69 function. Relay 115 receivesbattery current over wire 96 and the return is ever wires 119 and 112,armature 104 and wire 106. Radio-frequency current passes from thetransformer 69 over wire 74, armature 115 and wires 121 and 92 to rail 3and from the transformer over wires 75 and 91 to rail 2. As block F isoccupied, caution or low frequency current will pass to the rails bloct:E. Relay 80 is de-energized, its battery circuit being opened by droppedarmature 15.

But as stated before, the occupancy of this biocl-z prevents asufficient amount of this current passing along the rails beyond theoccupying train to be appreciated by the oncoming train. Relay E isde-energized beause relay E is short-circuited by train TT.

1 illustrates an installation adapted or a block comprising threecut-sections. ration A. is similar in all respects to stations F and issimilarly controlled. As

I D and blocks B and C are unoccupied, signal A indicates clear. Theentrance cut-section comprising rails 6 and 7 being occupied by vehicleT, electro-magnetic flux should be there present and it flows fromsecondary winding 7 2 of station A over wire 74, armature 114 wires 120,98, 84, and 123, armature 124 wires 125, 84 and 87, primary winding 88of transformer 89, wires 86, 83 and 126, armature 124 wires 127, 83 and102, armature 14 and wires 103 and 73 to the winding 72. Relay 124 isenergized by track battery 128 connected to rails 4 and 5. As soon asthis vehicle T, Fig. 1) passes onto rails 4 and 5, this relay 124 isshort-circuited and opens the circuit to transformer 89 but closes thecircuit to transformer 132 from wire 127 over dropped armature 124 andwire 133 to primary windin g 134, the secondary winding 135 beingconnected to the rails 4 and 5 by wires 136 and 130 and by wires 137 and129. The return from transformer 132 is by wire 138 and armature 124 towire 123. As soon as vehicle T runs onto rails 2 and 3, relay 14 becomesde-energized, relay 114 also becomes de-energized, but relay 115 picksup its armature and radiofrequency current passes to rails 2 and 3 asbefore described.

it the end of the controlled territory the installation shown in Fig. 6is located for the purpose of transmitting radio-frequency currents ofboth wave lengths above spoken of upon therails of the tracksimultaneously so that the automatic control instrumentallties on thelocomotive will be locked in nonbraking position where they remain untilcontrolled territory is again entered. This installation is controlledby the presence of a vehicle T on the rails 2 and 3 to which areconnected the wires and 141 which lead from the battery 142, whichnormally energizes relay 17 of the next station in the rear. As soon assaid relay 17 is short-circuited, the circuit from the battery in Fig. 6to relay 15 of the next station in the rear is opened, which circuit isfrom said battery 13 of the station shown in Fig. 6 over wires 142 and143, armature 144", wires 1 5 and 84, wire 99 of the next station in therear, relay 15, wire 100, armature 17 wires 101 and 83 to the stationshown in Fig. 6, wire 146, relay 147, wire 148, armature 144 and wire149 to the battery. But this circuit is open so relay 147 isdeenergized, closing circuits to both relays 30 and. both relays 150shown in Fig. 6, as follows. From the battery 13 shown in Fig. 6, wire142 connects to relay 150 on the right while a branch 152 connects toadjacent relay 30. W ire 153 connects this relay 30 to wire 154extending to armature 147 and this connects to the battery by wire 149.For the installation on the left, wire 155 connects the battery to relay150, while the branch 156 connects to adjacent relay 30 which isconnected to armature 147 by wire 157 from which the branch 158 connectsto relay 150. Armature 147 is connect-ed to the battery by wire 149.

The radio-frequency currents are conducted to rail 2 by wire 74,armature 150, wires 160, 161, and 141, and to rail 3 by wires 75, 162and 140. The relays shown and designated as 16 and 144 are part of thesignalling system and are there preferably slow-acting. They are hereinshown as such, but quick acting relays will serve the same purpose inthe present installations.

hen a train leaves uncontrolled and enters controlled territory, themechanism 'shown at the left in Fig. l-may be used to inform theengineer by means of lamps R and G of the condition of the controlmecha- 1 nism. The relay 165 shown here is a part of the signal systemand may be disregarded. The track battery 85 connects to the rails 6 and7 and normally energizes the relay 166 which attracts its armatures aand b sothat a circuit from the line wires 8 and 9 to trans- 127, 83 and102, armature 14, wire 103, relay A wire 105, armature 16 and wire 106to the battery. When relay 104 becomes deenergized by its circuit beingopened by relay 166 being de-energized, while relay 14 is stillenergized, radio-frequency current passes out on wires 83 and 84 asbefore described. This current passes in part to transformer 89 so thatthe vehicle T may pick up its control current. But part passes overwires 168 and 169 to the primary winding 170 of transformer 167, whosesecondary winding 171 is connected to the grid of tube 172. The gridleak 173 of this tube connects to the winding 171 by wires 174, 175 and176. The filament of this tube is heated by current from the battery 177passing over wire 178 to the filament and the return being over wires179' and 180, dropped armature 166 and wire 182. When this grid isenergized, plate current passes fom line wire 8 over wire 183, relay184, and wire to the plate and from the filament over wires 178 and 186to wire 9. Energized relay 184 closes the circuit from battery 177 overwire 182, dropped armature 166 wire 180, armature 184 wire 187, safelamp G which is preferably green, and wires 188 and 175 to the battery.But if no radiofrequency current is present in wires 83* and 84 relay184 will not be energized and this battery current will flow fromdropped armature 184" over wire 190 to danger lamp R, which ispreferably red.

If lamp G receives current and the signals on thevehicle show eitherclear or caution conditions in the track ahead, or if lamp R isreceiving current andthe signals on the vehicle indicate danger, theengineer knows that both track and vehicle instrumentalities arefunctioning properly. If either lamp is receiving current and thesignals on the vehicle do not function properly to correspond, theengineer knows that the vehicle instrumentalities are out of order. Ifneither lamp shows current, he knows that the track installation nextahead is out of order. In an one of these cases, he is properlyforewarne Referring now to Figs. 7 and 8, which diagrammaticallyillustrate a signal installation of well known construction, the relays15, 16 and 17 are positioned substantially as shown in Figs. 1 to 6inclusive. Relay 15 is shown equipped with additional armatures b and cto control the signal or semaphore arm 204 which is mounted on a shaft203, the danger position when the block at whose entrance end it ispositioned is occupied, being vertical or clear when that block and thenext in advance are unoccupied, and being in intermediate position toindicate caution when the next block in advance is occupied. This shaft203 is rotated by means of a motor 205 and gears 206. i

The relay 15 is shown in Figs. 1 to 6 inclusive as a neutral relay, butwhen used in consemaphore being in horizontal or nection with a signalinstallation it is a polarneutral relay, having a polar armature 0. henblock D is occupied, no current passes over wires 99 and 101 to relay C,as before described, and armatures C and C drop because relays C and Care de-energized. No current passes to motor 205. Relay E is energizedwhen block F is unoccupied, for the reasons to be explained later on.vVhen relay E is energized, positive current flows from battery E overwires 96 and 97, armature 16", wires 98, 84 and 99 relay 15, wire 100,armature 17 wires 101, 83 and E relay 104, wire 105, armature 16 andwire 106 to the battery. This causes armature D to swing clock-wise, theother armatures of this relay being attracted. But if relay E werede-ener ized, current from battery E would flow over wires 96 and 97,armature 16% wire 105 and the circuit just named reversed, causingarmature 0 of relay D to swing counterclock-wise.

On the shaft 203 (Fig. 8) are three conductors in the form of plates193, 194 and 195, insulated from each other and from the shaft. Vhen theparts are as shown in Figs. '4' and 3, which occurs when relay 15 isde-energized because of the block in advance being occupied, no currentpasses to this signal installation. hen negative current passes to relav15 because of relay 16 of the next block in advance being tie-energized,current will fiow from battery 13 (Fig. 7) over wires 96, 97 and 200,motor 205, wire 197, plate 193, wire 196, armature 15 and wire 106 tothe battery. Motor 205 will turn its shaft about forty-five degrees andthus move plate 193 to break the circuit over wire 196. Other mechanismis provided to lock the motor but that is well known and need not bedescribed. Semaphore now holds its intermediate caution position. At thesame time, plate 194 connects wires 192 and 191 so that current willflow over wire 192, plate 194, wire 191, relay 16 and wire 201,energizing this relay which thereupon attracts its armatures and causespositive current to flow to the next station in the rear to relay 15 ofthat station. That relay swings its armature c clock-wise so that assoon as motor 205 of that station has turned forty-five degrees, plate195 on shaft 203 will connect wires 193 and 199 so that current willflow from the battery to the motor as before and then over the wires197, 199, plate 195, wire 193, armature 15 and wire 106. The motor willthereupon turn through additional forty-five degrees and until semaphore204 is vertical.

The direction of current from each battery 13 to relay 15 of the nextstation in the rear therefore controls the position of the semaphore ofthat next station and current in either direction results in relay 16being energized and relay 15 of the next station in the rear beingpositive energized.

The signal installation may therefore be said to be one block ahead ofthe control in stallation in indications, for the semaphore arm 204 atthe entrance end of a block indicates the character of radio-frequencycurrent which would be impressed upon the rails at the exit end of thatblock should that block be occupied, excepting that when the semaphoreis horizontal, no such current is impressed upon the rails.

The wires 83 and 84 therefore not only con duct the signal current whichis the control current for this control system but also theradio-frequency current to the entrance cutsections of the severalblocks which are of sufiicient length to warrant cut-sections. Thesignal batteries 13 and the track batteries of the signal system arethus made use of in this control system together with the line wires 83and 34 and the poles supporting them.

WVe claim 1. In a track installation to control railway trains, thecombination of a trackway divided into blocks each comprising aplurality of cut-sections, a current source and a track relay connectedto each cut-section, a radio-frequency current generator for each blockand comprising an output transformer embodying a secondary coil,connections between said secondary coil and the rails of the severalcut-sections, a relay for each cutsection to close said connectionsthereto, a current source, and circuits between said current source andsaid last named relays which are closed when said track relays aredeenergized.

2. In a train control system, the combination of a trackway divided intoblocks, each comprising a plurality of cut-sections, a radio-frequencycurrent generator at the exit end of one block embodying an outputwinding for said block, normally open circuits connecting said outputwinding to the exit end of the rails of each section, a track batteryconnected to one end and a track relay connected to the opposite end ofeach track section, a control relay having an armature adapted to causethe closing of the supply circuit for said generator, a current source,a circuit between said current source and said control relay whichcircuit is controlled by said track relays. and a relay for the circuitto each cut-section adapted to close the same when the track relaythereof is de-energized.

3. In a train control system, the combination of a trackway divided intoblocks, each comprising a plurality of sections, a radiofrequeneycurrent generator and embodying output windings normally disconnectedfrom the exit ends of the several block sections, a control relayadapted to normally hold open the supply circuit for said generator, acurrent source for said relay, a track battery connected to one end anda track relay connected to the opposite end of each track section, and acircuit between said current source and said control relay adapted to beopened when either of said track relays is short-circuited, and meanscontrolled by said track relays to close the circuit between said outputwinding and each section as the track relay thereof becomesshort-circuited.

4;. In a train control system comprising track rails divided into blocksand the blocks divided into sections, a generator for radiofrequencycurrents embodying an output transformer including output windings,normally open circuits connecting said windings to the rails of eachblock-section, and means controlled by the occupancy of each section tocause the closing in turn of said circuits between the output windingsand said blocksections as such block-sections are consecutivelyoccupied.

5. A train control system comprising track rails divided into blocks andthe blocks divided into sections, a generator for radiofrequencycurrents embodying an output transformer including output windings, andcircuits connecting said windings to the rails of each block-section andmeans whereby the occupancy of each bl0ck-section in turn causes thepassage of radio-frequency current to that section.

6. A train control system comprising track rails divided into blocks andthe blocks divided into sections, a generator for control current foreach block section and independent output windings for the severalsections of each block deriving energy from said generator, and circuitsconnecting said windings to the rails of each block-section and meanswhereby the occupancy of each block-section in turn causes the passageof control current to that section.

7. A train control system comprising track rails divided into blocks andthe blocks 1 divided into sections, a generator for radiofrequencycurrents embodying an cutput transformer including output windings, andwires connecting said windings to the rails of each block-section andmeans whereby the occupancy of one section of the block causes thetransmission of radio-frequency current to the rails of said sectionwithout affecting the other section of said block.

8. A train control system comprising rails divided into blocks and theblocks divided into sections, means for impressing radiofrequencycurrents of two different frequencies upon the rails of one of theblocks, said means embodying an out-put transformer, output windings,wires connecting said windings to the rails of each block-section, meansresponding to the occupancy of the block next in advance to predeterminethe frequency of such currents, and means responding to the occupancy ofa section to cause the impression of radio-frequency current on thatsection without affecting the other section of the block.

9. A train control system comprising track rails divided into blocks andthe blocks divided into sections, a source of alternating current, meansat each block for transforming said current into radio-frequencycurrents, normally inoperative means connected to each block-sectiontoconvey such currents to such block sections independently of eachother, means responsive to the presence or absence of trains in theblock ahead to determine the frequency of the currents thus impressed,and means responsive to the occupancy of each section to select themeans connecting the current transforming means to carry suchradiofrequency current to the occupied blocksections.

10. A train control system adapted to be installed in connection withthe signal system for a track divided into blocks and which embodiestrack batteries and relays which generate and control signallingcurrent, three-position semaphores and batteries for supplying currenttherefor, a generator for radio-frequency currents adapted to impresscurrents of different wave lengths upon the rails, and means controlledby the signalling current derived from said track batteries to selectthe wave length to correspond to the concntions indicated by thesemaphore.

11. A train control system adapted to be installed in connection withthe signal system for a track divided into blocks and the blocks dividedinto cut-sections, which system embodies track batteries and relays,three-position semaphores and batteries for supplying current therefor,and line wires between adj acent semaphores to carry the current forcontrolling said semaphores, a generator for radio-frequency currentsadapted to impress currents of different wave lengths upon the rails atexit end of each cut-section, means controlled by the currentcontrolling the semaphores to select the wave lengths to correspond tothe conditions indicated by the semaphores, and conductors from saidgenerators to said line wires and from said line wires to thecut-sections remote from said generators to conduct radio-frequencycurrents thereto.

THOMAS E. CLARK. JAMES E. CLARK.

